During the production of various metals, a vapor precursor halide is formed by thermal decomposition of a complex precursor salt. It is important to perform the decomposition in a system that is isolated from the atmosphere in order to obtain a volatile precursor halide with the desired purity and to prevent the formation of corrosive species by reaction of the formed precursor halide with water vapor present in the atmosphere. In previous processes, the solid complex precursor salt was heated in a fixed bed batch reactor or a rotary kiln, at approximately 700 degrees Celsius (° C.). These processes presented several limitations. In a fixed bed batch reactor, the heat transfer was limited and there was a considerable amount of down time to load and unload the reactor. On the other hand, using a rotary kiln in the previous process required dynamic hot seals. In addition, the rotary kiln had to be corrosion resistant. Consequently, the high capital cost of the rotary had a strong negative impact on the production cost of the precursor halide.
An additional problem in both previous processes was that the by-products left by the thermal decomposition were in powder or dust form. Thus, the by-products had very low apparent density, were difficult to handle and had low heat transfer properties.